In a funny way, fan fiction is the purest form of literary art there is, the one most untainted by commerce. It's hard to make money from it because someone else owns the intellectual property (unless you change the details just enough, in which case you can make quite a lot of money on it. Just ask E.L. James.)

Amazon's ready to change that. A new program called Kindle Worlds will let would-be writers publish, and profit from, fan-fictional e-books with the blessing of the original characters' creators, who will receive royalties from every sale. Call it a sort of open API for IP.

The revenue split is considerably less generous than authors who use their own characters enjoy, with Kindle Worlds writers keeping 35% of the net. That's for works over 10,000 words; for shorter ones, the rate is an even lower 20%. Ordinarily, writers who self-publish e-books through Amazon keep 70% percent.

Kindle Worlds could become big business when and if Amazon is able to obtain agreements with owners of some of the franchises that inspire the most ardent fan-fic followings. Those include "Harry Potter," "Twilight," "Star Wars," "Star Trek" and "Buffy the Vampire Slayer." While some authors disapprove of the practice, many of the top-selling genre writers, including J.K. Rowling, Stephenie Meyer and Joss Whedon, encourage use of their characters by fans.

It's also a way for Amazon to identify promising undiscovered writers it can sign to its Amazon Publishing book imprint. Established authors have been wary of signing with Amazon after seeing the difficulties that Tim Ferriss and others have had in getting competing retailers to carry their books.

One thing Kindle Worlds writers will not be able to publish is "slashfic," the term of art for pornographic or at least extremely sexual fan fiction. The Kindle Worlds guidelines prohibit "pornography or offensive depictions of graphic sexual acts." [Correction: As several commenters have helpfully noted, "slashfic" refers exclusively to the subgenre of sexual fan fiction that involves gay sex and/or relationships.]

That means, interestingly, that Amazon would likely not have published "The Master of the Universe," the "Twilight" takeoff that Random House reconstituted as the "Fifty Shades of Grey" series. Those three books have gone on to eclipse "Harry Potter" as the fastest selling novels of all time.